An example of a geographical information system adapted for use with a pointing device is described in the French patent application filed on 29 Mar. 2012, under number FR1252873 on behalf of France Telecom.
In the application No. FR1252873, it is recalled that, in prior-art techniques, to determine whether a pointing device is pointing at (i.e. is directed towards) a target device (the device that is being pointed at), the pointing device and the device pointed at must be designed to work together (one has a sender and the other a receiver capable of detecting a signal sent by the sender). For example, a television set typically comprises an infrared receiver capable of receiving infrared signals sent by a remote control unit supplied with this television set.
The major drawback of these prior-art techniques is that a communications channel has to be set up (by means of the sender/receiver pair) between the pointing device and the device pointed at. This leads to the creation of manufacturer-specific hardware of low upgradability entailing its own multiplicities.
The technique proposed in the application FR1252873 (the operation of which is described in detail further below with reference to FIGS. 1 and 2) consists of the use of a central unit to determine which device or devices are pointed at by the pointing device. This technique thus provides several advantages as compared with the above-mentioned prior-art techniques. Indeed, it is the central unit that obtains a piece of 3D pointing information, i.e. a piece of information indicating those devices, pointed at, towards which the pointing device is physically oriented, in a 3D space. It is therefore not necessary for the pointing device and the device or devices pointed at to be designed to work together (there is no need for one device to have a sender and the other to have a receiver matching the sender). For the central unit, knowledge of the 3D pointing information makes it possible to create an association between the pointing device and the device or devices pointed at. It is possible to create applications resulting from this association (especially but not exclusively to control the device pointed at by the pointing device).
However, the technique of the application FR1252873 can be further improved, especially in the use and the nature of the objects contained in the data base accessed by the central unit.